OB push-pull

[tinitus]

Hi, I have this OB thing spinning in my head

We have long known the theoretical advantages of a pushpull arrangement...improved symmetric drive and lower distortion
But honetsly, I havent been giving it much kredit

Besides when doing it like this the added woofer doesnt give more displacement, so whats the big deal

But now I am wondering whether there could actually be something to it
Maybe there really could be highly valueable gain from the improved symmetric drive and lowered distortion
Even small as it may be, it may still deliver some significant and important bass information, details that would normally have been masked and blurred

Just to clarify, this woofer OB "baffle" is actually a closed box, and something of a paradox that may be a major problem fore the many OB fans, who actually choose OB because they dont like boxes

Ofcourse woofer polarity is reversed, so both woofers move as one single dipole unit

edit, often rather cheap woofers are used, and especially those kind of woofers may really improve from this arrangement, and being low cost woofers, the added cost shouldnt cause much concern

Any thoughts about how this may work out in real life

[tinitus]

Heres another option with 3 woofers, a strange one

[AdamZuf]

The first design is sort of an open baffle - if you do wire the speakers out of phase then I would assume that OB rules of panel width (vs. extension) would apply... And if so, then whatever frequencies are in the passband of the box would not go from the back of the box to the front because it prevents them from doing so - the sound from the rear drivers will reach the ears from reflections and will not sum on the same phase as the front driver to cancel distortion, which is the reason for the whole thing.
Or maybe I'm getting it wrong...

Seems to me you would probably gain more from push pull open baffle I would assume, maybe someone did it.

For the second design, I don't see how a non idenctical number of drivers will make push-pull work - the thing has to be "mirror like" in respect to driver specs, and of coarse they change uppon doubling the drivers.

[tinitus]

My, I had forgot all about that crazy idea


Your absolutely right, it seem much better to just do it the ordinary way, and get the advantage of having both drivers on front

I seems a high cost to "hide" one driver on back just to get dipole action
Whats it supposed to do anyway

I didnt see it before, and why I asked

The disadvantages are almost obvious, so I will try focus on maybe possible advantages

1. Its pushpull, and without any ugly magnet sticking out
And its LOADED pushpull

2. Its way better to have only one woofer fore smooth transistion to a mid or tweeter

3. Here comes the tricky part
Will it have low end roll off like a closed box, or like a dipole, or both
Would this mean that better "low" Qts woofers could be used

But one driver moving in and other moving out, how will that affect calculation of "box"